Microscope objective

ABSTRACT

A five component microscope objective has a numerical aperture of 1.25. When used with a telescope as described in U.S. Pat. No. 3,355,234 and an immersion oil, the objective provides a magnification of 100×X in an embodiment having a focal length of 1.824 mm and is well corrected for the usual chromatic image aberrations, spherical aberration, coma and astigmatism.

BACKGROUND OF THE INVENTION

This invention relates to microscope objectives and more particularly to microscope objectives having a numerical aperture of substantially 1.25 and a magnification of 100×, when used with a telescope objective as described in U.S. Pat. No. 3,355,234, an immersion oil and having a focal length of 1.824 mm.

Microscope objectives according to this invention are well corrected for the usual chromatic image aberrations, spherical aberration, coma and astigmatism when used with a telescope objective and have a substantially flat image field.

U.S. Pat. No. 3,598,474, issued Aug. 10, 1971, discloses a five component oil immersion objective having an N.A. of 1.25. While the components have the same general configuration as the corresponding components of the present invention, the specific curves, spacings, thicknesses and glasses are different.

U.S. Pat. No. 3,902,793, issued Sept. 2, 1975, discloses a five component oil immersion objective having an N.A. of 1.25. While the components have the same general configurations as the corresponding components of the present invention, the specific curves, spacings, thicknesses and glasses differ.

U.S. Pat. No. 3,912,378, issued Oct. 14, 1975, discloses a five component oil immersion objective having an N.A. of 1.35. While most components have the same general configuration as the corresponding components of the present invention, the number of elements in three of the components is different as well as specific curves, thicknesses, spacings and glasses.

DESCRIPTION OF THE DRAWING AND INVENTION

The drawing is an optical diagram of an embodiment of the present invention.

Referring to the drawing, objective XX is shown in a view transverse to its optical axis relative to object plane 0 and illustrates the lens components aligned along the optical axis. The first component I of objective XX is a plano-convex positive doublet followed by second lens component II, which is a concavo-convex positive singlet. Third lens component III and fourth lens component IV are biconvex positive doublets. Fifth lens component V is a convex-concavo positive doublet. Doublet components III and IV each have convex-concavo first elements and biconvex second elements, while doublet component V has a biconvex first element and a biconcavo second element.

The parameters of objectives according to the present invention are set forth in Table I, wherein successive axial spaces are identified as S₁ to S₅ and axial thicknesses of successive lens elements are identified as T₁ to T₉. The radii of successive lens surfaces are designated R₁ to R₁₄ with the minus sign (-) being applied to the radius of a surface whose center of curvature lies on the object side of its vertex. The refractive indices and Abbe numbers of the successive lenses are absolute values designated ND₁ to ND₉ and ν₁ to ν₉ successively.

                                      TABLE I                                      __________________________________________________________________________                            Refractive                                                                               Abbe                                             Radius  Thickness                                                                            Spacing                                                                              Index     No                                            Lens                                                                              (R)     (T)   (S)   (ND)      (ν)                                        __________________________________________________________________________                      S.sub.1 = 0.148f                                                 R.sub.1 = ∞                                                                      T.sub.1 = 0.313f                                                                           1.53 < ND.sub.1 < 1.55                                                                   50 < ν.sub.1 < 52                          I  R.sub.2 = -0.583f                                                                      T.sub.2 = 1.469f                                                                           1.87 < ND.sub.2 < 1.89                                                                   40 < ν.sub.2 < 42                             R.sub.3 = -1.356f                                                                            S.sub.2 = 0.011f                                                 R.sub.4 = -7.791f                                                           II         T.sub.3 = 1.096f                                                                           1.78 < ND.sub.3 < 1.80                                                                   46.5 < ν.sub.3 < 48.5                         R.sub.5 = -3.448f                                                                            S.sub.3 = 0.872f                                                 R.sub.6 = 7.582f                                                                       T.sub.4 = 0.658f                                                                           1.77 < ND.sub.4 < 1.79                                                                   25 < ν.sub.4 < 27                          III                                                                               R.sub.7 = 4.404f                                                                       T.sub.5 = 2.632f                                                                           1.43 < ND.sub.5 < 1.45                                                                   94.5 < ν.sub.5 < 96.5                         R.sub.8 = -4.404f                                                                            S.sub.4 = 0.027f                                                 R.sub.9 = 12.084f                                                                      T.sub.6 = 0.658f                                                                           1.77 < ND.sub.6 < 1.79                                                                   25 < ν.sub.6 < 27                          IV R.sub.10 = 3.284f                                                                      T.sub.7 = 2.522f                                                                           1.43 < ND.sub.7 < 1.45                                                                   94.5 < ν.sub.7 < 96.5                         R.sub.11 = -9.956f                                                                           S.sub.5 = 8.728f                                                 R.sub.12 = 78.162f                                                                     T.sub.8 = 1.371f                                                                           1.77 < ND.sub.8 < 1.79                                                                   25 < ν.sub.8 < 27                          V  R.sub.13 = - 3.448f                                                                    T.sub.9 = 0.828f                                                                           1.60 < ND.sub.9 < 1.62                                                                   43.5 < ν.sub.9 < 45.5                         R.sub.14 = 4.342f                                                           wherein f = 1.8 to 1.85 mm.                                                    __________________________________________________________________________

Table II presents the preferred embodiment wherein f=1.824 mm.

                                      TABLE II                                     __________________________________________________________________________                             Refractive                                                                            Abbe                                               Radius   Thickness                                                                            Spacing                                                                              Index  No                                              Lens                                                                              (R)      (T)   (S)   (ND)   (ν)                                          __________________________________________________________________________                       S.sub.1 = 0.27                                                  R.sub.1 = ∞                                                                       T.sub.1 = 0.57                                                                             ND.sub.1 = 1.540                                                                      ν.sub.1 = 51.1                               I  R.sub.2 = -1.063                                                                        T.sub.2 = 2.68                                                                             ND.sub.2 = 1.883                                                                      ν.sub.2 = 40.8                                  R.sub.3 = -2.473                                                                              S.sub.2 = 0.02                                                  R.sub.4 = -14.210                                                           II          T.sub.3 = 2.00                                                                             ND.sub.3 = 1.788                                                                      ν.sub.3 = 47.4                                  R.sub.5 = -6.290                                                                              S.sub.3 = 1.59                                                  R.sub.6 = 13.830                                                                        T.sub.4 = 1.20                                                                             ND.sub.4 = 1.784                                                                      ν.sub.4 = 26.1                               III                                                                               R.sub. 7 = 8.033                                                                        T.sub.5 = 4.80                                                                             ND.sub.5 = 1.434                                                                      ν.sub.5 = 95.6                                  R.sub.8 = -8.033                                                                              S.sub.4 = 0.05                                                  R.sub.9 = 22.042                                                                        T.sub.6 = 1.20                                                                             ND.sub.6 = 1.784                                                                      ν.sub.6 = 26.1                               IV R.sub.10 = 5.990                                                                        T.sub.7 = 4.60                                                                             ND.sub.7 = 1.434                                                                      ν.sub.7 = 95.6                                  R.sub.11 = -18.160                                                                            S.sub.5 = 15.92                                                 R.sub.12 = 142.568                                                                      T.sub.8 = 2.50                                                                             ND.sub.8 =0 1.784                                                                     ν.sub.8 = 26.1                               V  R.sub.13 = -6.290                                                                       T.sub.9 = 1.51                                                                             ND.sub.9 = 1.613                                                                      ν.sub.9 = 44.3                                  R.sub.14 = 7.920                                                            __________________________________________________________________________ 

What is claimed:
 1. A five-component microscope objective having an N.A. of 1.25 comprising a plano-convex doublet I, a concavo-convex singlet II, a biconvex doublet III, a biconvex doublet IV and a convex-concavo doublet V having the following parameters:

    ______________________________________                                                 Radius       Thickness Spacing                                         Lens    (R)          (T)       (S)                                             ______________________________________                                                                        S.sub.1 = 0.148f                                        R.sub.1 = ∞                                                                           T.sub.1 = 0.313f                                          I       R.sub.2 = -0.583f                                                                           T.sub.2 = 1.469f                                                  R.sub.3 = -1.356f                                                                                     S.sub.2  = 0.011f                                       R.sub.4 = -7.791f                                                      II                   T.sub.3 = 1.096f                                                  R.sub.5 = -3.448f                                                                                     S.sub.3 = 0.872f                                        R.sub.6 = 7.582f                                                                            T.sub.4  = 0.658f                                         III     R.sub.7  = 4.404f                                                                           T.sub.5 = 2.632f                                                  R.sub. 8 = -4.404f                                                                                    S.sub.4 = 0.027f                                        R.sub.9 = 12.084f                                                                           T.sub.6 = 0.658f                                          IV      R.sub.10 = 3.284f                                                                           T.sub.7 = 2.522f                                                  R.sub.11 = -9.956f                                                                                    S.sub.5 = 8.728f                                        R.sub.12 = 78.162f                                                                          T.sub.8 = 1.371f                                          V       R.sub.13 = -3.448f                                                                          T.sub.9 = 0.828f                                                  R.sub.14 = 4.342f                                                      ______________________________________                                                       Refractive    Abbe                                                             Index         No                                                          Lens (ND)          (ν)                                             ______________________________________                                                       1.53 < ND.sub.1 < 1.55                                                                       50< ν.sub.1 < 52                                         I                                                                                   1.87 < ND.sub.2 < 1.89                                                                       40 < ν.sub.2 < 42                                        II   1.78 < ND.sub.3 < 1.80                                                                       46.5 < ν.sub.3 < 48.5                                         1.77 < ND.sub.4 < 1.79                                                                       25< ν.sub.4 < 27                                         III                                                                                 1.43 < ND.sub.5 < 1.45                                                                       94.5 < ν.sub.5 < 96.5                                         1.77 < ND.sub.6 < 1.79                                                                       25 < ν.sub.6 < 27                                        IV                                                                                  1.43 < ND.sub.7 < 1.45                                                                       94.5 < ν.sub.7 < 96.5                                         1.77 < ND.sub.8 < 1.79                                                                       25 < ν.sub.8 < 27                                        V                                                                                   1.60 < ND.sub.9 < 1.62                                                                       43.5 < ν.sub.9 < 45.5                           ______________________________________                                          wherein f = 1.8 to 1.85 mm.                                              


2. The objective of claim 1 wherein f is 1.824 mm, ND₁ is 1.540, ND₂ is 1.883, ND₃ is 1.788, ND₄ and ND₆ and ND₈ are 1.784, ND₅ and ND₇ are 1.434, ND₉, is 1.613, ν₁ is 51.1, ν₂ is 40.8, ν₃ is 47.4, ν₄ and ν₆ and ν₈ are 26.1, ν₅ and ν₇ are 95.6, and ν₉ is 44.3. 